Crystal for watches and like articles.



L. E. F. WACHTER.

CRYSTAL FOR WATCHES AND LIKE ARTICLES.

APPLICATION FILED OCT.17,19II.

Patented Dec. 17, 1918.

LOUIS E. F. waoncrnn,onnn w YORK, N. Y.

CRYSTAL FOR WATCHES AND LIKE ARTICLES.

Specification of Letters Patent.

Patented Dec. 17, 1918.

Application filed October 17, 1917. Serial No. 197,006.

To all whom it may concern: 7

Be it known that I, LOUIS E. F. WAcH'rnR, a citizen of the United States, residing in the city, county, and State of New York, have invented certain new and useful I mprovementsin Crystals for Watches and" l ke Articles, of which the following is a speclfication, reference being had to-the accompanying drawings, illustrative of one particular embodiment of my invention.

This invention relates to .crystals for watches, that is crystals as the term broadly applies, meaning a transparent protecting cover such as put over the face and hands of a watch, clock or other article permitting visibility of the dial and hands, and at the same time the necessary degree of protection therefor. In particular the invention relates to the use of celluloid or other transparent materials instead of glass, which involves material the physical characteristics of which necessitate new methods of attachment. Among the objects of this invention I provide better means of overcoming the difficulties in attaching celluloid or like material, and secure them by means which assure under all conditions a tight joint between the transparent disk and the attaching rim under the varying conditions to which the material is subjected. l accomplish this by making a pliable, resilient and transparent face cover, the form and construction of which is such that any shrinkage which might take place will not produce a loosening in the joint, which may be due to selfadjustment or other inter-relation of the:

parts.

The demand for non-breakable watch crystals necessitates the production of an article which would overcome all the great disadvantage which such crystals possess', in particular the loosening of the same from its fastenings due to shrinkage, owing to the character of the composition of such nonbreakable crystals. In order that such a crystal may be retained securely in the bezel regardless of shrinkage, efforts have been made by way of attempting to rigidly secure the rim by pinching in a groove in the metal of the bezel, and other 'methods have been suggested, but without success. In view of the softness of celluloid and other compounds, such non-breakable crystals cannot in practice he fashioned with a sharp edge to hold in the groove of a bezel such as the usual glass crystal, nor have various other suggestions proven practical.

Furthermore, in some constructions heretofore suggested such thickness of material is required as to be obstructive, and also would increase the cost, and in the case of some celluloids would result in the field being f0ggy,'all of which characteristics prevent commercial usefulness.

My invention provides means for overcoming the various difliculties referred to as will appear from the description and the drawing forming a part hereof, in which:

The figure shows a diametrical cross-section of a crystal in which,the crystal B has the wall I) outwardly inclined, ofi'set at an abrupt angle from the face of the crystal,

and in the outer side of this wall agroove b,

' crystal B has the edge 6 extending laterally to such an extent as to maintain the attachment without being afiected by the contraction or expansion of the main body of the crystal, or, in other words, compensating for such variations in dimensions which are liable to occur in the matter of celluloid or like material, due to the results of seasoning or temperature variations.

Variations in the thickness and dimensions of material become important in'the new art of use of celluloid for watches and like articles, but b the practice of my invention relatively t in material may be used for the face or transparent closure, whereby the desired elasticity and spring'for insertion and otherwise, can be provided,'and pro er transparency in such'materials as cellu oid is assured, combined with the various other ad vantageous features necessary for commercial success,

What 'I claim and desire to secure by Letters Patent is:

In a watch crystal having an undercut beveled edge on its periphery and an outwardly extending portion below said beveled edge extending beyond the latter, said beveled edge being adapted to engage the inner edge of the opening of a bezel, and said outwardly extending portion being adapted to engage the under surface of the bezel around vits opening.

Signed at New York, this 16th day of October, 1917 7 LOUIS E. WACHTER. Witnesses:

' H. MUGHMORE,

HERMANN F. Cnn' rz. 

